Problems and questions regarding the Youtube Tutorial

i watched the whole tutorial (https://www.youtube.com/watch?v=Lhuq8mZr8bg&ab_channel=Nowa) and built an app where you can login and see some data from the firebase database. But I dont want to show every user the same content. i want to show only the records, which are connected to a user. Is this possible? How can i do that? I am still encountering two problems as well. The listview shows only 1 record, but there are 4 in the database (same problem like in the video). 2. On the dashboard page i cannot greet the user, because the firebase elements are not available in texts, but only in circuit. (see screenshot)
Bildschirmfoto 2024-04-26 um 11.52.27